Wireless networks are increasingly used in media delivery, in particular using some form of broadcast and streaming. Media consumption on wireless devices is growing at a very fast rate, with the advent of very capable smartphones and tablets that can deliver a good user experience. This puts a huge burden on wireless networks, which have to handle this media delivery as well as all other services ranging from voice to broadband data.
To deliver media to wireless devices, a wireless network uses a wireless channel. The quality of the wireless channel affects the ability of the network to reliably deliver the media. The quality of the wireless channel may vary depending on a number of factors, such as the distance of the wireless device to the base station, the current load on the base station, and so on. The network can adapt media streaming to the quality of the wireless channel by using multiple data quality descriptions of the same content and/or by adjusting the transport format used by the base station.
As an example, multiple data quality descriptions could be used to compress a small time section of a movie to various levels of quality. The highest data quality description would have no or very low distortion and would require the greatest number of bits. The lowest data quality description would have the most distortion and would require the fewest number of bits. Users in the best channel conditions may be able to receive the highest data quality description. Users in the worst channel conditions, typically at cell edge, may only be able to receive lower data quality descriptions, affecting their experience.
As mentioned above, the transport format used by the base station may also be adapted to the quality of the wireless channel. For example, the base station may select transport format characteristics, such as error control coding, modulation, multiple input/multiple output (MIMO) streams, etc., in order to target a certain block error rate (BLER) or other reliability level at the receiver. In general, a lower quality channel requires a more robust transport format that carries fewer information bits for the same resources (e.g., time, frequency, MIMO streams, and/or other resources).
Media delivery can overburden the network because network resources are limited and there is contention for the resources among different media content as well as among different services, such as voice, messaging, applications, etc., each with different quality of service requirements. Solutions are necessary to reduce the burden on the network associated with media delivery.